Re: [PATCH v3 4/6] drm/panel: simple: Add support for Samsung LSN122DL01-C01 2560x1600 panel

From: Thierry Reding <thierry.reding@gmail.com>
To: Doug Anderson <dianders@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Emil Velikov <emil.l.velikov@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>,
	Rob Herring <robh+dt@kernel.org>,
	Kumar Gala <galak@codeaurora.org>
Subject: Re: [PATCH v3 4/6] drm/panel: simple: Add support for Samsung LSN122DL01-C01 2560x1600 panel
Date: Tue, 14 Jun 2016 10:57:49 +0200	[thread overview]
Message-ID: <20160614085749.GB24442@ulmo.ba.sec> (raw)
In-Reply-To: <CAD=FV=VL0KgZnpjvAvYgK8rzgntKL2N0D6QbG6V0LO8vkaQkig@mail.gmail.com>

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On Mon, Jun 13, 2016 at 10:00:45AM -0700, Doug Anderson wrote:
> Yakir,
> 
> On Sat, Jun 11, 2016 at 7:56 PM, Yakir Yang <ykk@rock-chips.com> wrote:
> > The Samsung LSN122DL01-C01 is an 12.2" 2560x1600 (WQXGA) TFT-LCD panel
> > connected using eDP interfaces.
> >
> > Signed-off-by: Yakir Yang <ykk@rock-chips.com>
> > ---
> > Changes in v3:
> > - Correct the size of panel_desc to active area 262mmx164mm (Emil, Stéphane)
> >
> > Changes in v2: None
> >
> >  drivers/gpu/drm/panel/panel-simple.c | 25 +++++++++++++++++++++++++
> >  1 file changed, 25 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
> > index 2d40a21..17cc973 100644
> > --- a/drivers/gpu/drm/panel/panel-simple.c
> > +++ b/drivers/gpu/drm/panel/panel-simple.c
> > @@ -1246,6 +1246,28 @@ static const struct panel_desc qd43003c0_40 = {
> >         .bus_format = MEDIA_BUS_FMT_RGB888_1X24,
> >  };
> >
> > +static const struct drm_display_mode samsung_lsn122dl01_c01_mode = {
> > +       .clock = 271560,
> > +       .hdisplay = 2560,
> > +       .hsync_start = 2560 + 48,
> > +       .hsync_end = 2560 + 48 + 32,
> > +       .htotal = 2560 + 48 + 32 + 80,
> > +       .vdisplay = 1600,
> > +       .vsync_start = 1600 + 2,
> > +       .vsync_end = 1600 + 2 + 5,
> > +       .vtotal = 1600 + 2 + 5 + 57,
> > +       .vrefresh = 60,
> > +};
> > +
> > +static const struct panel_desc samsung_lsn122dl01_c01 = {
> > +       .modes = &samsung_lsn122dl01_c01_mode,
> > +       .num_modes = 1,
> > +       .size = {
> > +               .width = 262,
> > +               .height = 164,
> 
> Earlier you said that the active area of this panel was:
> 
> > Display area     262.656(H) X 164.16(V)         (12.2”diagonal)
> 
> In other panels I looked at the EDID tended to round numbers, not
> truncate them.  For instance the Starry panel that I sent the patch
> for says in the manual "262.7712 (H) x 164.232 (V)" but then the EDID
> says "263 x 164".
> 
> That would mean your width should be 263 mm, not 262 mm.

Yes, rounding is what I've also applied to all panels that I added.
While it isn't documented I hope that other panels did round, rather
than truncate, as well.

Thierry

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